I am a firm believer in the phrase” Why
Re Invent the wheel”. This antenna is a plumbers dream.Most parts are available on the World Wide
Web or at some larger hardware stores. This two-element Cubical Quad antenna
is designed for use on either the 10-meter ham band or the 11-meter Citizen’s
Band.

When all was said and done, my SWR
readings were 1.3 to 1.7 on the 10-meter band. At one point during the tuning
phase, I had a reading of 1 to 1 at about 29.5 MHz. I tried to stay with an
age-old design but also used commercially available parts. This kept the weight
factor manageable for a 10 or 11-meter size quad. My PVC version sports
vertical polarity plus an easy to change coaxial feed to the driven element.

The thing turned out quite well cosmetically
and I was very pleased with the electrical properties. I was involved in
building a similar antenna in the mid 60ties.Back then, we all had CB Radios. The basic design hasn’t evolved
much but the construction material has.This antenna weighs just about 20 pounds, the sixties version was nearly
45 lbs and all wood.

The Boom is 63 inches from end to
end. I used 60 inches of 1 ½ inch sch 40 PVC pipe. The pipe is secured to the
end hubs with ¼ x 2 ½ inch stainless machine thread carriage bolts and nuts. By
not cementing these in place, it allowed me to construct each end section one
at a time. It also makes any future repair allot easier. The two 5 way hubs
that support the spreader arms are also PVC. These came from an on-line
greenhouse building supply company.

With the help of 8
reducers from an on-line hardware company, the hubs will accept ½ inch sch 40
PVC pipe (See Update). The ½ inch PVC pipe sections are 12 inches long
(15 for the CB Band ). A 4-way one-inch slot is cut in one end.These slots allow 1 ½” stainless hose clamps
to secure the ½ inch dia by 72 inch solid fiberglass spreader arms. This design
makes for easy adjustment of the spreader arms.

The fiberglass spreader arms were once
electric fence posts in a previous life. These too are from an on-line electric
fence supply Co. On the end of each spreader arm, I attached a 2-inch long by
1-inch diameter section of black nylon rod. I ordered a 3-foot section from an On-Line
plastic supply company and cut them to length on my table saw. I drilled a
½ inch centered 1-inch deep hole in each. I secured the nylon tips with
friction and a dab of hot glue. These tips support the 12 ga. stranded Primary
wire that I purchased from a local automotive supply store.The opposite end of each nylon tip has a
1/8-inch dia hole drilled from side to side for passing the wire through. I
placed it ½ inch from the top of each piece.

I used the dimensions from an on-line quad
calculator to provide the exact length wire needed for the reflector and the
driven element. I measured these very precisely but left about 6 inches of
extra wire on each end.The wire has a
white plastic coating. I used a black marker to mark off each quarter length. I
colored ½ inch on either side of that mark with a red marker. This made
adjustment simple when I slid the fiberglass rods out to their proper
position.I secured the wire in place
with small nylon pull ties and a dab of hot glue on either side of the nylon
tips.

The reflector wire is cut at the beginning
of the first red mark and at the end of the last. I striped the coating back
1-inch on each end. I then overlapped and soldered the two ends together. (A
second person here helps to flex the rod to one side until the solder is cool.)
With the soldered joint securely inside the nylon tip, the fiberglass rods can
be extended to their proper length. The wire should be taut on all four
sections. After tightening the hose clamps, this completed the reflector loop.

.
The Boom mounting plate uses two stainless 1 7/8th exhaust clamps
and two 1 ¼” mast clamps. This picture shows a piece of aluminum plate ¼” x 4”
x 12”. I drilled and attached the plate to the boom centered and plumbed. The aluminum plate and the stainless clamps came from
That on-line auction or buy-now web company.

Moving to the business end of the boom, the
supporting structures are exactly the same as the reflector end with only one
minor change. The beginning and end of the driven element are attached at
either of the horizontal spreader arms. At this tip, I expanded the 1/8th
hole to a 3/8th hole. I placed a 2 ½ by 3/8th inch machine thread
nylon retaining bolt here as an attachment point for either end of the wire. I
needed a thin machine thread nut so I sawed one in half. After tapping the bolt
into place, I was left with one half of the nut on either side of the nylon
tip. I secured the nut with a small bit of hot glue. I drilled 1/8th
inch holes through the nylon bolt on either side of the nuts parallel to the
boom to secure the element wires. Now I threaded the wire through the tips.

I placed the black mark at the center of
the nylon tip then carefully held the wire in-place and passed the correct
amount of wire through the 1/8 inch hole and secured it in place with a pull
tie and hot glue. I repeated this on the opposite side of the tip. I did this
to make certain each wire was the same length as the other 2 sections. It only
took seconds to do this but it takes a lot of words to describe the process.

After securing the wires with wire ties and
hot glue, I was left with 2 short ends. I stripped the covering off each end
exposing copper to the black marks. At this point, I slid the last spreader arm
out to take up the slack in the wires and tightened the stainless hose clamp.

If you look at the next to last picture,
you will see a small aluminum project box. I attached an SO 239 at one end for
a direct RG 58 cable feed to the driven element loop. Two output wires are
attached inside the project box. One of the wires is attached to the center
connection of the SO 239 and the other to the metal box.I drilled two holes and installed rubber
grommets to the other end of the box to protect the output feed wires. An
optional balun could be installed here in place of the simple project box.I also installed one U bolt to attach the
box to the spreader arm just below the attachment points

I stripped out about 6 inches of coax
shield from some spare RG58 cable and divided this in two. I drilled a small
hole next to each grommet as attachment points for small ring connectors. I
secured these with sheet metal screws.I slid a section of shield down each short feed wire and soldered part
of the shield to the ring connectors. I slid a piece of shrink tubing down each
wire. I soldered each wire to a feed point and slid the shrink tubing over the
joints. I slid the braid up to the beginning of the plastic coating on one of
the element wires and secured it with a pull tie.

At this point, I
attached my SWR meter and started adjusting the braid exposing more or less of
the unshielded portion of the remaining feed wire until I achieved the lowest
SWR. I used another pull tie and covered the braids with electrical tape. This
completed the antenna. Either one of the charts below should give you the
needed dimensions for the 11Meter CB band or 10 meter dimensions for hams that
hold Tech class privileges and above. I used the second chart. <S>

Element Length

In Inches

Finished

Length

Each Side

Total

Arm Dimension In Inches:

From Boom

Center Line to End of Tips

11

Meter CB Center Freq:

27.205 CH 20

Element Length

In Inches

Finished

Length

Each Side In

Total

Arm Dimension In Inches:

From Boom

Center Line to End of Tips

10

Meter Ham Center Freq:

28.4

Reflector:

454 3/8

113 5/8

80 3/8

Boom

Pipe:

Reflector:

435 ¼

108 13/16

77

Boom

Pipe:

Driven:

443 1/4

110 7/8

78 3/8

62

Inches

Driven:

424 5/8

106 1/8

75

60

Inches

One last thing, I had to buy a short piece
of clear ½” dia. plastic tubing and cut it into 2 inch sections. I slid two
pieces onto each of the fiberglass spreaders before inserting them into the
12-inch spreader supports. Seems the ½ inch dia. PVC pipe, isn’t ½ inch inside,
its 5/8th. One of those small problems a person building something from
scratch runs into from time to time. N1UUE Mexico, Maine.

Note:
Project Part Sources and
Links-Video There is an optional balun that might replace the
direct connection project box. It should give acceptable SWR readings on either
the 10 or 11 meter version. It uses the same SO 239 52 ohm input and the
output uses two thumbscrew connections. The net weight is 3.9 pounds.
The weight could be a problem if installed where the project box is
connected. Another challenge would be designing a mounting plate with
U-bolts to attach it to the Fiberglass spreader. If I decide to upgrade the RF
feed, I will do a bit more research before ordering this item. It looks a
bit pricy but I also believe "you get what you pay for". <S>
This upgrade should improve reception a bit and also refine the signal
radiation pattern. N1UUE - 73's

Balun - 2:1, High
Power, 1.8 to 30 MHz, Cast Aluminum Gasketed Enclosure - DXE-BAL100-H11-C.I located this item on the following
website.DX Engineering.com